© Bücker und Funk 2018   -    Rev43  04/2018
With this short report we want to provide you an overview what was going on since our last project update – most of it within the year 2017.

Certification

The French type certificate for the FK131 Jungmann had been achieved within end of 2016. In Germany we had to make four attempts to pass the very high noise limit requirements. Finally we found one type of silencer in combination with the matching propeller and aftersilencer which did allow us to achive the noise test certificate. In second half of the year 2017 the chief of the certification office “LSGB” from Braunschweig visited us in Speyer to make the type inspection and check the sample aircraft to stay within the LTFUL weight limit of less than 297,5 kg. To the end of the season 2017 we had completed all outstanding flighttests and were able to supply the full documentation set. We were expecting to get the German TC issued within 2017 but due to high workload at the administration the process has not been closed yet. Meantime there were ongoing discussions about future regulation for Ultralight definition in Europe. The European parliament decided that a modification in max take off weight will be part of the new aviation basic regulation. As there are also other things included (such as new regulation for drone and remote controlled aircraft) this regulation has not been closed for now. But at least we know two things which are for sure: 1. The EU MTOW for ultralights including rescue system will become 525kg in future. 2. Each nation can define their own system if wanted, up to an MTOW of 600kg. Now the good question is how far will existing aircraft comply to new regulation? Of course a safe answer can only be made as soon the new regulation is published – in detail! And remember: the details are defined by national authorities, not by Brussel! But there are some aircraft where it is at least very likely that these will not run into big trouble to fulfill new requirements. The FK131 could be one of those. The reason is that the design was made from the very beginning to comply with acrobatic requirements according CS23 and the initial MTOW was already estimated to be 525 kg.

Production

Since we noticed an ongoing demand for the FK131 as well as the LSA and Experimental version BF131 in the last 18 month we focused on increasing the production capacities for these projects. Up to spring 2016 the manufacturing of the FK131 has been organized entirely at PodesvaAir company in the Czech Republic. The BF131 at our polish production partner ASK. Since middle of 2017 both companies are working as partners. They have different duties, now there are composite and fairing parts produced in Poland which are also used by our Czech partner. Vice versa in Czech are landing gear, tailplane and control parts produced which are used in the polish production. A third companie in Czech Republic was added to enforce capacities. This company is producing wings and fuselage frames which are supplied to PodesvaAir and ASK. Meantime PodesvaAir was moving into an entirely new facility in the end of 2017. Of course the movement had a bad effect on production flow inside 2017, but from now on we can expect an improved situation from there. Also at ASK there were significant investments done to renew and enlarge production space inside 2017. Beside its activities for Jungmann production ASK is also authorized manufacturing partner for the FK12 Comet as well as for the FK14 Polaris meanwhile.

Design

An updated version of the Fk131 has been launched in 2017. We call it the “FK131A1 Jungmann” Version. For example we did invest a lot of money to get the original steel tubing with 0,75mm wall produced for us - same as the original Bücker fuselages had been built from. They will replace the common 1,0mm wall tubes (with smaller diameters) as used in most steel frame fuselages. These tubes do not exist anymore today-so we had to order a large quantity to get them manufactured specially for us. As a result the fuselages will have bigger diameter tubes and so become more stiff (solid) and do appear absolutely scale - by same weight! This will make the FK131A1 and BF131B fuselages nearly identical – allowing engines up to 150hp. Another example is that we took copies of fairing parts from an original Jungmann. We produced molds for them and now we can get these parts done in composite. Advantage is not only that they are lighter. More than that these parts are showing the exact authentic surface with all details, joints, rivets asf. And they have a weight of app. 1/3rd of original parts... The original Bücker metal seats are reproduced in Carbon-Kevlar now and will replace the wooden seat type. They will save weight, improve strength and look more authentic. A new, reshaped engine nosecone and fairings gets the “face” of the plane very original according the Bü131B cowling. We work on some more changes; all of them intended to make the aircraft more authentic in detail or to improve it where possible. An entirely new and crash protective fuel tank made from Kevlar has been developed and tested. A fire protective new composite firewall design was prepared and tested and so on. One detail which appeared to become very difficult to realize was a new carbon type interplane wire structure. Our target is to replace the original steel wires inside the wing (expensive and complex) by industrial machined (extruded) carbon profile wires. Obviously no one had been trying something similar before. It took us nearly two years and a significant amount of tests until we finally came to a design which proved to be stronger but lighter and less complex than the original steel structure! At the end all these modifications will become another improvement of the project – in details of course. They may finally make the difference at the end to other replica projects …

BF131B production

The manufacturing of the B type saw progress in 2017. Kit airframes had been produced for the US market. Unfortunately we have been unable to complete the first B Jungmann with LOM engine – as the delivery of the engine had been delayed for more than a year by LOM. And on top it is very likely that LOM will not go ahead with production of piston engines (existing engines will get serviced of course). There is no available option for a four cylinder inline air-cooled engine in the >100hp category worldwide. So (in worst case) this project might be continued in future with some kind of Lycoming or other engine conversion…
News 2016 News 2016 News 2017 News 2017

FK131 and BF 131Jungmann projekt update

Jan. 3rd, 2018